Added AssetGraph.prototype.queue.
Added AssetGraph.prototype.queue.

assetgraph/assetgraph,papandreou/assetgraph,slang800/assetgraph,jscinoz/assetgraph,slang800/assetgraph,jscinoz/assetgraph,papandreou/assetgraph,papandreou/assetgraph,jscinoz/assetgraph